The present application relates to an optical sensor element, and an imaging device and electronic equipment using the same, and further to a memory element and electronic equipment using the same. The present application relates more particularly to a configuration using a semiconductor layer made of an oxide semiconductor.
Recent years have seen increasingly multifunctional electronic equipment incorporating a flat display device such as liquid crystal or organic EL display device. Such multifunctionality includes screen input such as touch panel and pen input and backlight brightness control made possible by an optical sensor element provided on the display screen or in proximity thereto. Optical sensor elements and elements adapted to drive such electronic equipment which are provided in the electronic equipment use a semiconductor layer made of amorphous silicon or polycrystalline silicon crystallized by eximer laser or solid phase growth.
Further, a configuration using an oxide semiconductor has been proposed in recent years. Such an oxide semiconductor can be formed using an inexpensive sputter system for use as the semiconductor layer. For instance, JP-T-2006-502597 describes an example in which a thin film transistor is used as a drive element of the display device. This transistor uses a semiconductor layer made of an oxide semiconductor such as ZnO, SnO2 or In2O3. As another example, Japanese Patent Laid-Open No. 2006-165530 discloses an X-ray sensor using an amorphous metal oxide semiconductor.